This invention generally relates to polishing devices, more particularly to hand-operable or portable devices that are suitable for restoring the surface finish to substrates that have an extensive surface area. The portable polisher according to this invention includes a pair of polishing rolls or buffs that are securely mounted onto a respective pair of elongated arbors that rotate along their respective longitudinal axes in a counter-rotating manner by the operation of a drive assembly that rotates one arbor in a clockwise direction and the other arbor in a counterclockwise direction. Buffs according to this invention, which are for mounting over the respective arbors, include a plurality of disposable fabric disks that are axially compacted together.
In industries such as aircraft maintenance and sheet metal working, it is often necessary to improve the surface characteristics and to enhance the surface appearance of substrates such as metal sheets, particularly sheet aluminum. In this regard, the aircraft industry demands specialty aluminum sheeting for fabrication over aircraft framing to thereby construct the outer skin of aircraft. This specialty sheeting and the constructed aircraft skin should be free of blemishes, corrosion and oxidation. While it is possible to paint or otherwise coat these types of surfaces, an unpainted, highly polished aluminum skin is more corrosion-resistant than a painted aluminum surface, which must also be periodically stripped and repainted, requiring toxic chemicals and expensive special facilities. Moreover, a polished aircraft skin enhances the economical operation of an aircraft because it is lighter in weight and exhibits less drag than a painted aluminum surface.
Because of these advantages, it is desirable to utilize polished aluminum sheeting to fabricate aircraft skin. However, this desirable approach does have certain disadvantages in that any blemishes thereon cannot be simply covered up, as would be the case for a painted surface. This requires high surface quality standards during the manufacture of such aluminum sheeting, as well as special care during subsequent handling thereof including shipment, storage, skin construction, and in-use maintenance. When this type of sheeting is made at the mill, it is subjected to a very high speed in-line polishing operation which imparts a highly polished surface to mill-sized webs of sheet aluminum. Such large in-line polishers are very effective in imparting the needed finish to these specialty products. However, immediately after these specialty sheets are manufactured, they are susceptible to being scratched, discolored or otherwise blemished by handling and transport devices, by the environment, and by human handling, particularly during operations such as fabricating the sheeting into the aircraft skin.
Accordingly, there is a need for a means by which surface blemishes can be repaired or removed after such highly polished specialty sheets are prepared at the mill. Certain attempts have been made in this regard by providing portable polishing units which are intended to achieve spot polishing of these blemishes. Typically, these portable polishing units impart a rotary sweep to a relatively flat buffing disk which is usually spindle-mounted.
Such units have proven less than satisfactory when compared with the results attained by large in-line polishers used at a specialty mill. Units of this type do not achieve the uniform surface finish characteristics of a finish applied at the mill. They tend to leave an uneven finish within which buffing marks are visible. Additionally, these devices, although portable, can be difficult to control because of their tendency to "walk" along the surface. Furthermore, since these specialty sheetings are exceptionally thin and pure, portable polishing units, which typically do not provide the precision polishing of the in-line apparatus used at the mill, run the risk of actually removing the thin, pure aluminum surface that is characteristic of this sheeting. In addition, previously known portable polishing units and buffs typically do not attain mill-like polished characteristics, or such characteristics are attained only after the expenditure of considerable time and effort and usually require a worker who has achieved considerable polishing skills.
Therefore, there is a need for a portable polishing apparatus which is easily controlled by a single operator, that can impart a mill-like finish with minimal risk of damaging the surface of specialty sheeting such as highly polished aluminum, and that can attain such a finish in a relatively short length of time and without requiring an exceptionally skilled operator.
Such is accomplished according to the present invention by providing a portable polishing apparatus having a pair of elongated rotatable buffs, each of which rotates along its longitudinal axis. Each such longitudinal axis is generally parallel to the surface being polished, and the pairs of buffs counter-rotate with respect to each other, one of the buffs rotating in a clockwise direction, another rotating in the counterclockwise direction, these buffs including a plurality of fabric disks that are axially compacted together. Polishing of structures such as the undersurface of aircraft can be facilitated by including a universal mount assembly that combines the portable polisher with a power-assisted lift assembly.
Accordingly, general objects of the present invention include providing an improved portable polisher and specialty buffs and mount assemblies therefor.
Another object of this invention is to provide compactly assembled buffs that are especially suitable for an improved, lightweight polisher having a pair of elongated counter-rotating buffs which are generally parallel to the surface being polished.
Another object of the present invention is to provide improved buffs for a portable polisher, which buffs minimize the polishing time and skill needed to meet commercial scale polishing requirements during fabrication and maintenance of sheet metal equipment such as aircraft bodies.
Another object of the present invention is to provide an improved portable apparatus and buffs therefor for surface repair or surface preparation of a variety of substrates.
Another object of this invention is to provide an improved portable device and buffs therefor for restoring the polished finish of aluminum aircraft skin after it has been dulled by normal use.
Another object of the present invention is to provide an improved portable device and buffs therefor for repairing blemishes on polished aluminum sheeting that occurs during handling, transport, and fabrication.
Another object of this invention is a portable polisher and buffs therefor for removing oxidation or other blemishes quickly and efficiently without substantial removal of thin, pure aluminum surfaces.
Another object of the present invention is to provide means and method for conveniently applying polishing compounds during the operation of a polishing device having counter-rotating longitudinal compactly assembled buffers.
Another object of this invention is to provide an improved longitudinal buff and method of making same, which buff resists flattening thereof and resultant drag on the surface being polished, thereby increasing surface speed at a given, constant power input to produce improved polishing action.
Another object of the present invention is to provide an improved elongated fabric buff, which is structured to increase the extent that the dressed or cut fabric edges are in contact with the surface being polished and to decrease the extent of contact between fabric sides and the surface being polished, which increases the efficiency with which the buff brightens and polishes the surface.
Another object of this invention is to provide buffs that allow for minimal fabric removal to satisfactorily dress the buffs after they have been in use, particularly when the buffs are provided with end chamfers.
Another object of the present invention is to provide an improved portable polisher having a handle assembly that facilitates remote operation thereof, as well as improved buffs therefor.
Another object of this invention is to provide an improved polisher adapted to be vertically supported by a power-assisted lift assembly for polishing structures such as the undersurface of aircraft.